The present invention provides a large format fingerprint capture apparatus, system and method that is low power, compact, and lightweight and has a platen area greater than 3.0 square inches. The present system is typically powered, controlled, and exchanges data over a single data/control/power connection to a host PC, e.g., a desk top computer, PDA, or laptop computer although the system can also be used in a wireless fashion with a power subsystem so no physical connections are required.
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1. A system configured to generate a composite image of a friction ridge signature of a subject, the system comprising: a platen comprising a first light-reflecting surface; a light source configured to emit light rays to illuminate a subject placed in contact with the first light-reflecting surface of the platen; a camera configured to capture images of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner; and a processor configured to receive images of the subject captured by the camera, and to automatically determine whether a sequence of the received images includes a successful capture sequence, wherein a determination that the sequence of received images includes a successful capture sequence is made responsive to identification by the processor of a trigger in the sequence of received images indicating the beginning of a capture sequence and identification by the processor of a trigger in the sequence of received images indicating the completion of the capture sequence.
A fingerprint scanning system captures and combines images to create a complete fingerprint image. It includes a transparent surface (platen) where a finger is placed. A light source illuminates the finger on the platen. A camera captures a continuous stream of images of the finger through the platen. A processor analyzes these images to automatically detect the start and end of a successful fingerprint capture sequence. It identifies a "trigger" in the image sequence that signals the capture start, and another trigger signaling the capture end. These triggers initiate and complete the fingerprint capture process.
2. The system of claim 1 , wherein processor is configured to determine a type of capture sequence, and to determine whether the sequence of received images includes a successful capture sequence of the determined type.
The fingerprint system described previously also determines the *type* of fingerprint capture being performed (e.g., roll or slap) before determining whether a successful capture sequence of that specific type has occurred. This enables the system to adapt its image processing based on the expected motion and characteristics of different capture methods. For example, it might adjust the acceptance criteria to better handle a rolling motion versus a static finger press.
3. The system of claim 2 , wherein the type of capture sequence comprises a roll capture or a slap capture.
In the fingerprint system, the "type of capture sequence" that the processor determines can be either a "roll capture" (where the finger is rolled across the platen) or a "slap capture" (where the finger is pressed flat onto the platen). The system is able to distinguish between these capture types, which require different image processing techniques to produce an accurate final fingerprint image.
4. The system of claim 1 , wherein the processor is configured to generate, responsive to determination that the sequence of received images includes a successful capture sequence, a composite image, wherein the composite image is formed from the images included in the successful capture sequence.
When the fingerprint system determines that a successful fingerprint capture sequence has occurred (as previously described), it automatically generates a composite fingerprint image. This composite image is created using only the images that were part of the identified successful capture sequence, excluding any images before the start trigger or after the end trigger. This creates a clean final image.
5. The system of claim 4 , wherein the processor is configured to generate the composite image by merging the images included in the successful capture sequence.
The system described previously generates the composite fingerprint image by merging together the individual images that were included in the successful capture sequence. This merging process combines the information from multiple frames to create a more complete and accurate representation of the fingerprint, filling in gaps and reducing noise.
6. The system of claim 1 , wherein the processor is configured to identify the trigger indicating the beginning of the capture sequence by comparing successive images in the sequence of received images.
The fingerprint capture system identifies the "trigger" that indicates the beginning of a capture sequence by comparing successive images in the continuous stream of images being captured. For instance, the algorithm looks for changes between frames like increased ridge detail/contrast or movement to identify the start of fingerprint placement.
7. The system of claim 1 , wherein the processor is configured to identify the trigger indicating the completion of the capture sequence by comparing images in the sequence of received images that were captured subsequent to the trigger indicating the beginning of the capture sequence.
The system identifies the "trigger" indicating the *completion* of the fingerprint capture sequence by comparing images captured *after* the trigger indicating the beginning of the capture. The system looks for characteristics such as lack of further ridge movement, or decreasing contact area, to signal the end of an effective capture.
8. A method of generating a composite image of a friction ridge signature of a subject, the method comprising: emitting light rays toward a platen comprising a first light-reflecting surface to illuminate a subject placed in contact with the first light-reflecting surface of the platen; capturing images of the subject in contact with the first light-reflecting surface of the platen, through the platen, in an ongoing manner; and executing one or more modules on one or more processors to automatically determine whether a sequence of the received images includes a successful capture sequence, wherein a determination that the sequence of received images includes a successful capture sequence is made responsive to identification by the processor of a trigger in the sequence of received images indicating the beginning of a capture sequence and identification by the processor of a trigger in the sequence of received images indicating the completion of the capture sequence.
A method for generating a complete fingerprint image involves using a transparent surface (platen) where a finger is placed, and illuminating the finger on the platen with light. Images of the finger are captured continuously. Software modules analyze these images to automatically detect the start and end of a successful fingerprint capture sequence. The start and end are signaled by "triggers" identified within the sequence of captured images.
9. The method of claim 8 , wherein determining whether a sequence of the received images includes a successful capture sequence comprises: determining a type of capture sequence, and determining whether the sequence of received images includes a successful capture sequence of the determined type.
The fingerprint capture method described above refines the process of determining a successful capture sequence by first identifying the *type* of capture (e.g., roll or slap) and then determining if a successful capture sequence *of that specific type* has occurred. This allows the method to adapt to different capture methods requiring unique processing.
10. The method of claim 9 , wherein the type of capture sequence comprises a roll capture or a slap capture.
In the fingerprint capture method, the "type of capture sequence" can be either a "roll capture" or a "slap capture." The method can distinguish between these two capture styles and apply appropriate image processing.
11. The method of claim 8 , further comprising generating, responsive to determination that the sequence of received images includes a successful capture sequence, a composite image, wherein the composite image is formed from the images included in the successful capture sequence.
The fingerprint capture method detailed above also includes generating a composite fingerprint image when a successful capture sequence is identified. The composite image is created from only the images included in the successful capture sequence, improving image quality by excluding extraneous frames.
12. The method of claim 11 , wherein the composite image is generated by merging the images included in the successful capture sequence.
In the fingerprint capture method, the composite image is generated by merging the images included in the successful capture sequence. This merging creates a more detailed fingerprint image by combining features from multiple frames.
13. The method of claim 8 , wherein identification of the trigger indicating the beginning of the capture sequence is performed by comparing successive images in the sequence of received images.
The fingerprint capture method identifies the trigger indicating the *beginning* of the capture sequence by comparing successive images in the stream of images. Image differences, such as increased ridge presence or motion, can trigger the start of the capture window.
14. The method of claim 8 , wherein identification of the trigger indicating the completion of the capture sequence is performed by comparing images in the sequence of received images that were captured subsequent to the trigger indicating the beginning of the capture sequence.
The fingerprint capture method identifies the trigger that signals the *end* of the fingerprint capture sequence by comparing images captured *after* the trigger indicating the beginning of the capture. Characteristics like stable ridge patterns or decreasing contact signal capture completion.
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December 8, 2011
September 24, 2013
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